Hildenbrandia ardreae Pedroche, 2024

Pedroche, Francisco F., 2024, Hildenbrandia ardreae sp. nov. (Rhodophyta), recorded before as Hildenbrandia dawsonii (nom. inval.), Phytotaxa 666 (4), pp. 291-297 : 296

Hildenbrandia ardreae Pedroche sp. nov.

Hildenbrandia canariensis var. dawsonii Ardré, 1959, p. 230 , pl. 3: fig. 6 nom. inval.; Hildenbrandia dawsonii (Ardré) Hollenberg, 1971 b, p. 286 nom. inval.

Description: Thallus saxicolous, dull reddish color, depending upon the thickness of the crust, closely adherent to the substrate. The crust thickness is as much as 300 µm, consisting of densely packed quadrate or sometimes somewhat elongated cells 4–5 µm wide and 6–9 μm long, arranged in vertical rows; conceptacles immersed, sub-spherical to compressed, shallow, 80–100 µm wide, 35–90 µm deep with a prominent but rather irregularly defined ostiole usually slightly below the surface; tetrasporangia subcylindrical to fusiform, 23–30 µm long, 7–11.5 µm wide and divided regularly and zonately by parallel transverse walls. There are no irregularly divided sporangia. There are no paraphyses.

Tetrasporangia from the Cedros collection corresponded to Ardré’s description. Divisions of the tetrasporangia are parallel, and the conceptacles look approximately like Ardré’s figures ( Fig. 1B ).

Holotype: MEXICO: Punta Norte, Cedros Island, Pacific coast of Baja California (28°22’26” N; 115°13’21” W), 30 October 1951, leg. E. Y. Dawson ( AHFH 57949 in UC1853247 , Fig. 2E , specimen 10572).

Paratype: MEXICO: 10 miles west of Punta Malarrimo, Bahía Vizcaíno, Pacific coast of Baja California, 17 April, 1951, leg. E.Y. Dawson (Dawson´s slide 1690, AHFH 55561 in UC1883773).

Etymology: The species is named after Françoise Ardré (1931–2010), who recognized this taxon as a new entity.

Crustose specimens were generally dried in the shade without formalin, and there is enough material to explore for DNA extraction.

Figures

FIGURE 1. Hildenbrandia conceptacles.A. Hildenbrandia dawsonii (after Hollenberg, 1971).B. Hildenbrandia canariensis var. dawsonii (after Ardré, 1959).

FIGURE 2. A–E. Hildenbrandia specimens (labeled as Hildenbrandia prototypus var. kerguelensis) at UC. A. AHFH 55561 in UC 1883773. B–C. Dawson´s specimens in box 9962, all from 10 miles west of Punta Malarrimo, Bahia Vizcaino, Baja California. D–E. HOLOTYPE of Hildenbrandia ardreae, Dawson´s specimen in box 10572 from Punta Norte, Isla Cedros, Baja California (AHFH 57949 in UC 1853247).